>> reporter: good evening, diane. tonight, police officers across this whole region feel they are under attack. police headquarters here on lockdown. every entrance, every exit, heavily guarded. the entire police force in america's second largest city, essentially held hostage to one man who is allegedly bent on revenge. tonight, by air, land and sea, an all-out manhunt. the suspect, one of their own. 33-year-old christopher dorner. a former lapd officer, now an alleged cop killer. police say he isn't just targeting cops, but their families, too. >> this has gone far enough. you know, nobody else needs to die. >> reporter: the killing spree started sunday in orange county, with the baffling double murder of a popular college basketball coach and her fiance. monica quan and keith laurence, shot in cold blood as they sat in their car. only last night did authorities put two and two together. quan is the daughter of retired lapd captain randy quan, who was instrumental in getting christopher dorner fired. in a rambling m